1. Field of the Invention
This invention relates to weaving and more particularly to an improved flexible intermediate support for a weaving heddle frame.
2. Discussion of the Prior Art
As is well known, weaving comprises interlacing warp and filling yarns according to a predefined pattern. Each individual warp yarn is threaded through a heddle. The heddles are held in a weaving heddle frame. Each frame can be raised or lowered as desired, thus controlling the position of its heddles and warp yarn. That is, each respective set of warp yarns controlled by one of the frames can be raised or lowered relative to the other sets of warp yarns. A shuttle motion is used to pass the filling yarn under the warp yarns that have been raised by the frames and to pass it over those warp yarns that have been lowered by the remaining frames. The process is repeated with the frames being shifted so as to raise new sets of warp yarns and lower others between successive passes of the shuttle until the fabric is woven.
Weaving heddle frames, presently in industrial use, have upper and lower frame staves between which one or more intermediate supports extend. The number of intermediate supports required depends on the length of the weaving heddle frame. The intermediate supports stabilize the frames as they move up and down while weaving, insuring that the upper and lower staves of each frame reamin parallel and the desired distance apart so that the heddles do not bind and can slide freely on them.
None of the intermediate supports in the prior art is readily slideable on the staves; and in some instances, the supports must be entirely removed in order to relocate them and allow the heddles to slide properly. Unfortunately, weaving heddles take their final position only after the commencement of a weaving process. If the intermediate support is of a fixed position design, the support must be completely removed to allow the heddles and yarn ends to pass by it; and it must then be reinstalled. On the other hand, if the intermediate support is of a slideable design, fasteners on both the top and the bottom of the support must be loosened before it can be slid to the desired position and then secured in place again. In either case, removing or sliding intermediate supports is a time-consuming and difficult task in part because of the many fasteners which must be loosened and then tightened on both the upper and lower frame staves. Moreover, special tools are frequently required as well.
The problems which arise in connection with the installation and removal of the intermediate supports are compounded by the facts that the number of weaving heddle frames in a weaving heddle loom is large, ranging from six to thirty-two. Further, the frames are very close together. To gain access to an intermediate support, the operator must spread the top frame staves apart and reach down between the frames to loosen or tighten the required fasteners.
Rigid intermediate supports for weaving heddle frames are shown in U.S. Pat. Nos. 4,658,864, 4,635,685, 3,417,790, 2,909,199, and 2,037,381. Various problems involved in the installation and removal of such intermediate supports are disclosed in these patents. In particular, U.S. Pat. No. 4,658,864 shows an intermediate support having threaded screws which are located on the underside of the lower frame stave making them almost inaccessible. U.S. Pat. No. 4,635,685 also shows a combination in which two screws must be replaced on the lower stave. A slideable intermediate support shown in U.S. Pat. No. 3,417,790 is held in position by two screws on the lower stave as well as two on the underside of the upper stave. Relocating this support presents an added problem in that guides to insure that it is being secured in a vertical position, perpendicular to the staves, are missing.
Other rigid intermediate supports are disclosed in U.S. Pat. Nos. 2,909,199 and 2,037,381. The latter support comprises a rigid rod surrounded by a hollow tube. The rigid rod must be raised completely in order to remove the tube and allow the heddles to slide by. U.S. Pat. No. 2,909,199 also discloses a rigid rod which must be raised through the upper frame stave to allow the heddles to slide past the intermediate support.
U.S. Pat. No. 4,475,574, on the other hand, shows a flexible intermediate support connected to the heddle carrying rods; but this support is not fixedly mounted on the frame staves and transmits only tensile forces between the rods. In the event compressive forces were to act on the rods during a weaving process, this intermediate support could be dislodged, causing disaster.
In my prior pending U.S. patent application identified above, there has been disclosed an intermediate support for a weaving heddle frame that carries both tensile and compressive forces between the upper and lower frame staves, in which the lower end of the support is easily connected to or removed from the lower frame stave. This intermediate support comprises a flexible cable on which is strung a segmented, rigid hollow member. The cable is retained in a position perpendicular to the upper and lower frame staves with the use of slotted holders fixedly attached thereto. The slotted holder on the lower stave is also employed to retain an end plug connected to the cable. The only fasteners on the intermediate support which must be alternately loosened and tightened are those disposed in a cable tensioning device mounted at the top of the upper frame stave, making the fasteners easily accessible and eliminating the use of any fasteners which must be loosened or tightened under the upper frame stave.
When the tensioning device in this intermediate support is employed to apply tension to the cable, the end plug presses against the holder, lifting the lower frame stave upwardly and into contact with the lower end of the rigid hollow member. Simultaneously, the upper frame stave is forced downwardly and into contact with the upper end of the rigid hollow member. Thus the cable transmits a tensile force while the rigid hollow member carries a compressive force, as required to maintain the upper and lower frame staves in a desired predetermined parallel relationship with each other so that the heddle can slide freely, without binding, along heddle carrying rods of the weaving heddle frame.
In certain weaving heddle frames, the position of the heddle carrying rods relative to the frame staves requires that an intermediate support in which the upper and lower ends of the rigid hollow member contact the upper and lower frame staves, include offsets. These offsets, when needed, are formed in those portions of the rigid hollow member contiguous with the heddle carrying rods. Unfortunately, such offsets tend to reduce the strength of the intermediate support when it acts as column exerting compressive loads between the upper and lower frame staves.